package test;


import javax.swing.tree.TreeNode;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;

public class BinaryTree {
    static class TreeNode {
        public char val;
        public TreeNode left;//存储左孩子的引用
        public TreeNode right;//存储右孩子的引用

        public TreeNode(char val) {
            this.val = val;
        }
    }

    public TreeNode createTree() {
        TreeNode A = new TreeNode('A');
        TreeNode B = new TreeNode('B');
        TreeNode C = new TreeNode('C');
        TreeNode D = new TreeNode('D');
        TreeNode E = new TreeNode('E');
        TreeNode F = new TreeNode('F');
        TreeNode G = new TreeNode('G');
        TreeNode H = new TreeNode('H');
        A.left = B;
        A.right = C;
        B.left = D;
        B.right = E;
        C.left = F;
        C.right = G;
        E.right = H;
        return A;

    }

    //前序遍历
    void preOrder(TreeNode root) {
        if (root == null) {
            return;
        }
        System.out.println(root.val + "");
        preOrder(root.left);
        preOrder(root.right);

    }

    //中序遍历
    void inOrder(TreeNode root) {
        if (root == null) {
            return;
        }
        preOrder(root.left);
        System.out.println(root.val + "");
        preOrder(root.right);
    }

    //后序遍历
    void postOrder(TreeNode root) {
        if (root == null) {
            return;
        }
        preOrder(root.left);
        preOrder(root.right);
        System.out.println(root.val + "");
    }


    public int size(TreeNode root) {
        if (root == null) {
            return 0;
        }
        return size(root.left) + size(root.right) + 1;
    }

    public static int learSize;

    // 获取叶子节点的个数
    public void getLeafNodeCount(TreeNode root) {
        if (root == null) {
            return;
        }
        if (root.left == null && root.right == null) {
            learSize++;
        }
        getLeafNodeCount(root.left);
        getLeafNodeCount(root.right);
    }

    public int getLeafNodeCount2(TreeNode root) {
        if (root == null) {
            return 0;
        }
        if (root.left == null && root.right == null) {
            return 1;
        }
        return getLeafNodeCount2(root.left) + getLeafNodeCount2(root.right);
    }

    //获取第k层节点的个数
    public int getKLevelNodeCount(TreeNode root, int k) {
        if (root == null) {
            return 0;
        }
        if (k == 1) {
            return 1;
        }
        return getKLevelNodeCount(root.left, k - 1)
                + getKLevelNodeCount(root.right, k - 1);
    }
    //求二叉树的高度
    public int getHeight(TreeNode root){
        if (root == null) {
            return 0;
        }
        int leftHeight = getHeight(root.left);
        int rightHeight = getHeight(root.right);
        return Math.max(leftHeight,rightHeight) + 1;
    }
    public TreeNode findVal(TreeNode root,char val){
        if (root == null) {
            return null;
        }
        if (root.val == val) {
            return root;
        }
        TreeNode leftT = findVal(root.left,val);
        if (leftT != null) {
            return leftT;
        }
        TreeNode rightT = findVal(root.right,val);
        if (rightT != null) {
            return rightT;
        }
        return null;
    }

    //寻找相同的二叉树
        public boolean isSameTree(TreeNode p, TreeNode q) {
            //1.先判断结构是否一样
            if(p != null && q == null || p == null && q != null){
                return false;
            }
            //上述条件满足则说明两颗数同时为空或者不为空
            if(p == null && q == null){
                return true;
            }
            //接下来两颗树都不为空,则判断值是否相同
            if(p.val != q.val){
                return false;
            }
            //都不为空且值一样，接下来判断左右子树是否相同
            return isSameTree(p.left,q.left) && isSameTree(p.right,q.right);
        }
    //翻转二叉树
        public TreeNode invertTree(TreeNode root) {
            if(root == null)return null;
            TreeNode temp = root.left;
            root.left = root.right;
            root.right = temp;
            invertTree(root.left);
            invertTree(root.right);
            return root;

        }
        //平衡二叉树
        public boolean isBalanced(TreeNode root) {
            if(root == null)return true;
            return getHeight2(root) >= 0;

        }
    public int getHeight2(TreeNode root){
        if (root == null) {
            return 0;
        }
        int leftHeight = getHeight2(root.left);
        if(leftHeight < 0){
            return -1;
        }
        int rightHeight = getHeight2(root.right);
        if(rightHeight >= 0 && Math.abs(leftHeight - rightHeight) <= 1){
            return Math.max(leftHeight,rightHeight) + 1;
        }else{
            return -1;
        }

    }
    //层序遍历
    public void levelOrder(TreeNode root){
        if (root == null) {
            return;
        }
        Queue<TreeNode> queue = new LinkedList<>();//使用队列实现
        queue.offer(root);
        while (!queue.isEmpty()){
            TreeNode cur = queue.poll();
            System.out.println(cur.val + "");
            if (cur.left != null) {
                queue.offer(cur.left);
            }
            if (cur.right == null) {
                queue.offer(cur.right);
            }
        }
        System.out.println();
    }
}

